London has been battered by 50mph winds that have felled trees and caused travel chaos. Powerful gusts swept across the capital as the Met Office issued a yellow "be aware" weather alert for most of the country.

Ministers have been told they cannot stop EU citizens from claiming child benefit for children who do not even live in the UK, the Evening Standard has learned.

Lawyers have ruled out a string of proposed schemes designed to allow the Government to refuse to pay out for children living in countries like Poland and the Czech Republic.

Among the schemes mooted by ministers were insisting that children live in the UK before they qualify for benefits. Another was to pay benefits at the much looser rates payable in the countries where the children live.

But a source said: “Everything ministers have suggested has been tested by the lawyers and deemed to be illegal.”

The equivalent to child benefit in Poland is worth around £20 a month. In the UK it is £81.20 for the first child and £53.60 for subsequent children.

The Prime Minister has ordered ministers to find savings ahead of an expected flood of migrants from Bulgaria and Romania in 2014.

Britons could lose part of their own welfare entitlement under proposals being considered. Weekly payments and healthcare would be more strongly linked to how long people have been paying into the system under the plans.

And councils would be encouraged to use existing powers to allocate social housing to people with local connections rather than newcomers.

The plans are being drawn up for David Cameron who is keen to reduce so-called benefit tourism from the European Union. Ministers fear a flood of migrant workers when people from Bulgaria and Romania are granted full rights under EU law in 2014.

Communities Secretary Eric Pickles said linking housing rights to local links was an “immensely sensible” idea.

“We’ve been urging local authorities to give priority to people coming out of the Armed Forces,” he said. “It does seem to me to be immensely sensible to ensure that if you work in an area or you’ve got a big connection - you might have been educated there or your family might be nearby – to receive some kind of priority in social housing.”

Ministers are refusing to say how many Romanians and Bulgarians are estimated to be coming to the UK to seek work.